D1.228 - Mitochondrial Epigenetic Programming: A Unifying Mechanism Linking Environmental Stress, Epithelial Barrier Dysfunction, and Allergy

Allergic diseases arise from impaired epithelial barrier integrity, oxidative stress, and persistent immune activation. Mitochondria regulate epithelial differentiation, redox balance, and inflammatory signaling, and their dysfunction amplifies allergic inflammation. Environmental stressors, including inflammatory cytokines and altered gravity conditions, disrupt mitochondrial homeostasis, leading to excessive reactive oxygen species, impaired mitochondrial biogenesis, and destabilization of epithelial identity. Conventional therapies target downstream inflammatory pathways but do not directly restore mitochondrial regulatory networks. We hypothesized that programmable epigenetic control of mitochondrial gene expression could restore mitochondrial and epithelial homeostasis under inflammatory and environmental stress.

Sequence-specific DNA-binding pyrrole–imidazole polyamides were designed to target mitochondrial regulatory loci, including peroxisome proliferator-activated receptor gamma coactivator-1α and associated transcriptional networks. These biomimetic epigenetic codes were evaluated in interleukin-13–induced airway epithelial inflammatory models and simulated microgravity cultures of human fibroblasts and mesenchymal stem cells. Mitochondrial function was assessed by mitochondrial DNA quantification, membrane potential assays, reactive oxygen species measurements, fluorescence imaging, transcriptome profiling, and quantitative gene expression analysis of mitochondrial and inflammatory pathways.

Inflammatory stimulation and simulated microgravity both induced mitochondrial dysfunction characterized by reduced cell viability, increased reactive oxygen species, mitochondrial fragmentation, loss of membrane potential, reduced mitochondrial DNA copy number, and suppression of mitochondrial regulatory genes including PGC-1α, TFAM, NRF1, and NRF2.  These changes were accompanied by transcriptomic suppression of mitochondrial and metabolic pathways and destabilization of epithelial and stromal cell homeostasis. Targeted epigenetic activation of mitochondrial regulatory loci restored mitochondrial gene expression, increased mitochondrial DNA copy number, improved mitochondrial membrane potential, and reduced oxidative stress under both inflammatory and microgravity stress conditions. Epigenetic mitochondrial programming produced more consistent restoration of mitochondrial function than pharmacological activation alone.

Environmental and inflammatory stress converge on mitochondrial dysfunction as a central mechanism driving epithelial instability and immune dysregulation in allergic disease. Direct epigenetic programming of mitochondrial regulatory networks restores mitochondrial quality control, redox balance, and cellular stability by acting upstream of inflammatory signaling pathways. These findings identify mitochondrial epigenetic regulation as a fundamental mechanism linking environmental stress, epithelial barrier integrity, and immune homeostasis, and establish a new therapeutic framework for allergic and inflammatory disorders.